Rational application of EGFR-TKI adjuvant therapy in patients with completely resected stage IB-IIIA EGFR-mutant NSCLC: a systematic review and meta-analysis of 11 randomized controlled trials

Purpose To determine the role and rational application of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) adjuvant therapy in patients with completely resected stage IB-IIIA EGFR-mutant non-small-cell lung cancer (NSCLC). Method Randomized controlled trials (RCTs) that compared the survival outcomes between adjuvant EGFR-TKIs and adjuvant chemotherapy or a placebo, or between different EGFR-TKI treatment durations for resected NSCLC, were eligible for inclusion. Disease-free survival (DFS) and overall survival (OS) with hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated as effective measures using random-effect or fixed-effect models. Subgroup analysis was also performed. Results Eleven RCTs involving 2102 EGFR-mutant NSCLC patients with or without EGFR-TKI adjuvant therapy were included. For all stage IB-IIIA NSCLC patients, EGFR-TKIs adjuvant therapy could not only significantly improve DFS (HR 0.43, 95% CI 0.30–0.63, P < 0.001) and 2- and 3-year DFS rates, but also improve OS (HR 0.72, 95% CI, 0.54–0.96, P = 0.024), compared with chemotherapy or the placebo. Further subgroup analyses indicated prolonged OS from first-generation EGFR-TKI adjuvant therapy in stage III patients, compared with chemotherapy or the placebo (HR for OS, 0.34; 95% CI, 0.18–0.63; P = 0.001). Of note, osimertinib adjuvant therapy led to the OS benefit expanding from stage III to stage II-III patients, with significantly improved DFS and a lower risk of brain recurrence, compared with the placebo. A 2-year treatment duration with EGFR-TKI adjuvant therapy showed a significantly lower recurrence risk than a ≤ 1-year duration. Conclusion The DFS advantage from first-generation EGFR-TKI adjuvant therapy can translate into an OS benefit in stage III NSCLC patients. Osimertinib might be more suitable for adjuvant therapy than first-generation EGFR-TKIs, because of the lower recurrence rate and the potential OS benefit even in early-stage patients. The optimal treatment duration for EGFR-TKIs at different stages of disease needs to be validated.